We are really looking forward to replacing our main transmitter at KOLU.  Many hours were spent in early spring working on the “driver” tube in the transmitter.  The old driver had been running well for around a year, but it was obvious it was “wearing out” as the output was falling due to lowering “emissions”, and it could no longer keep the transmitter running at full power.

Not to worry, we had 2 rebuilt tubes ready to place in the transmitter and bring it back to full power.  So, a trip was scheduled, and we carefully followed our replacement procedure with the rebuilt tube, set the transmitter to the initial burn-in settings at full power, and returned to the studio.  As I was entering a meeting, my cell-phone relayed a transmitter alarm that said transmitter power was very low.

Returning to the site, I noted that the output of the transmitter was low, but I could switch to lower power operation and the transmitter would be fine at that power level, so I continued to burn in the tube in case it needed more time.  After several days of this burn in, returning to the site I tried restoring full power, but stayed and watched the power decrease over a period of about an hour until it was less than the low power setting.

Okay…time to try the second rebuilt tube.  That one was placed in the transmitter and exhibited exactly the same symptoms.

At this point we reached our final option, which was to order a new tube at over twice the cost of the rebuilt ones, but new tubes seemed to work fine.  Another $2,000 spent…

Replacing the driver with the new tube, the burn-in process went back to normal and the transmitter has been working fine since then.  That is, until the final tube wears out, which should be in couple of months.

A new solid-state transmitter doesn’t use tubes and has much lower maintenance costs (and a warranty!).  Not only will it run cooler, use less electricity, and not require tubes, but it also positions us to where further upgrades could give us a “digital” signal, with more than one program stream that could be listened to on 90.1.  Stay tuned!